U.S. patent application number 17/258765 was filed with the patent office on 2021-04-29 for thermoplastic composition.
The applicant listed for this patent is DDP SPECIALTY ELECTRONIC MATERIALS US 9, LLC. Invention is credited to DETLEV HESSE.
Application Number | 20210122993 17/258765 |
Document ID | / |
Family ID | 1000005340630 |
Filed Date | 2021-04-29 |
![](/patent/app/20210122993/US20210122993A1-20210429\US20210122993A1-2021042)
United States Patent
Application |
20210122993 |
Kind Code |
A1 |
HESSE; DETLEV |
April 29, 2021 |
THERMOPLASTIC COMPOSITION
Abstract
Lubricant grease compositions comprising a silicone base stock
oil having a kinematic viscosity of from 20,000 to 100,000
mm.sup.2/s at 25.degree. C., a metal salt of a fatty acid wherein
the metal is selected from the group of lithium, calcium,
aluminium, barium titanium, zinc, magnesium and/or sodium; and a
suitable anti-wear additive.
Inventors: |
HESSE; DETLEV; (Wiesbaden,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DDP SPECIALTY ELECTRONIC MATERIALS US 9, LLC |
MIDLAND |
MI |
US |
|
|
Family ID: |
1000005340630 |
Appl. No.: |
17/258765 |
Filed: |
July 3, 2019 |
PCT Filed: |
July 3, 2019 |
PCT NO: |
PCT/US2019/040525 |
371 Date: |
January 8, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62699777 |
Jul 18, 2018 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10N 2040/04 20130101;
C10M 107/50 20130101; C10N 2030/12 20130101; C10M 117/04 20130101;
C10M 2207/1285 20130101; C10N 2050/10 20130101; C10M 2229/0415
20130101; C10M 169/00 20130101; C10N 2040/02 20130101; C10N 2030/06
20130101 |
International
Class: |
C10M 169/00 20060101
C10M169/00; C10M 107/50 20060101 C10M107/50; C10M 117/04 20060101
C10M117/04 |
Claims
1. A lubricating grease composition comprising (a) 65 to 89.9% by
weight of a silicone base stock oil having a kinematic viscosity of
from 20,000 to 100,000 mm.sup.2/s at 25.degree. C.; (b) 10 to 35%
by weight of a metal salt of a fatty acid wherein the metal is
selected from the group of lithium, calcium, aluminium, barium
titanium, zinc, magnesium and/or sodium; and (c) 0.1 to 2% by
weight of a suitable anti-wear additive.
2. A lubricant composition according to claim 1 where (a) is
selected from a silicone lubricant base stock oil of Group V, as
per the API classification of lubricant base oils or mixtures or
greases thereof.
3. A lubricant composition according to claim 1 where (a) is
selected from a silicone lubricant base stock oil trialkyl
terminated polydiethylsiloxane, trialkyl silyl terminated
polydimethylsiloxane, trialkyl silyl terminated
polydimethylmethylalkylsiloxane, or trialkyl silyl terminated
polymethylalkylsiloxane.
4. A lubricant composition according to claim 1 wherein component
(b) comprises one or more of the lithium monocarboxylic fatty acids
or lithium hydroxymonocarboxylic fatty acids, calcium
monocarboxylic fatty acids or calcium hydroxymonocarboxylic fatty
acids, aluminium monocarboxylic fatty acids or aluminium
hydroxymonocarboxylic fatty acids barium monocarboxylic fatty acids
or barium hydroxymonocarboxylic fatty acids and titanium
monocarboxylic fatty acids or titanium hydroxymonocarboxylic fatty
acids zinc monocarboxylic fatty acids or zinc hydroxymonocarboxylic
fatty acids, magnesium monocarboxylic fatty acids or magnesium
hydroxymonocarboxylic fatty acids and/or sodium monocarboxylic
fatty acids.
5. A lubricant composition according to claim 1 wherein component
(b) comprises one or more of, calcium, aluminium, barium and
titanium, zinc, magnesium and/or sodium salts of fatty acids
derived from animal oils or from vegetable oils.
6. A lubricant composition according to claim 1 wherein component
(b) comprises the metal salts of one or more of lauric acid,
myristic acid, palmitic acid, stearic acid, behenic acid,
myristoleic acid, palmitoleic acid, oleic acid, or a linoleic
acid.
7. A lubricant composition according to claim 1 wherein component
(b) comprise lithium salts of 12-hydroxystearic acid,
14-hydroxystearic acid, 16-hydroxystearic acid, 6-hydroxystearic
acid, or 9,10-hydroxystearic acid.
8. A lubricant composition according to claim 1 wherein component
(c) comprise zinc dithiophosphate, organic polysulphides,
phosphates, amine salt of sulphurized dibutyl hydrogen phosphate,
dialkyldithiophosphates dithiocarbamates dihydrocarbyl phosphate;
tricresyl phosphate sulphurized olefins, and sulphurized fatty acid
esters.
9. A lubricant composition according to claim 1 wherein the
composition may comprise up to 5% by weight of dry lubricant.
10. A lubricant composition according to claim 9 wherein the dry
lubricant may include one or more of graphite, molybdenum
disulphide, boron nitride, talc, polytetrafluoroethylene (PTFE),
calcium fluoride, cerium fluoride, or tungsten disulfide.
11. A lubricant composition according to claim 1 wherein the
composition additionally comprises one or more additives selected
from friction modifiers, extreme pressure additives, seal swelling
agents, rust and corrosion inhibitors, Viscosity Index improvers,
pour point depressants, anti-oxidants, free-radical scavengers,
hydroperoxide decomposers, metal passivators, surface active agents
such as detergents, emulsifiers, demulsifiers, defoamants,
compatibilizers, dispersants, deposit control additives, film
forming additives, tackifiers, antimicrobials, additives for
biodegradable lubricants, haze inhibitors, chromophores, and
limited slip additives and mixtures thereof.
12. A lubricant composition according to claim 11 wherein each of
the one or more additive(s) may be used at a level of from 0.01 to
10 wt % based on the total weight of the composition.
13. A method of lubricating, comprising the steps of: applying a
Use of a lubricant composition in accordance with claim 1 to
bearings in electric motors, wheel bearings, bearings in household
appliances, machine tools or aircraft accessories, small gear
drives, slow speed sliding applications, constant velocity joints,
ball joints, alternators, cooling fans, ball screws, chucks, linear
guides and machine tools, and dampen HiFi systems.
14. (canceled)
15. The method according to claim 13, wherein the lubricant
composition is able to lubricate at temperatures below -30.degree.
C.
Description
[0001] Disclosed herein are new lubricant compositions,
specifically lubricant grease compositions derived from high
viscosity polydimethylsiloxane base stock oils which can be
utilised for a variety of applications given the physical
properties thereof. Methods of making these compositions and their
uses are also described.
[0002] The primary purpose of lubrication is the separation of
solid surfaces moving relative to one another, to minimise friction
and wear. The materials most frequently used lubricants are oils
and greases with typically the choice of lubricant being largely
determined by the particular application.
[0003] Lubricating greases are generally employed where: [0004] (i)
heavy pressures exist; [0005] (ii) where oil drip from the solid
surfaces such as bearings is undesirable; or [0006] (iii) where the
motion of the contacting surfaces is discontinuous so that it is
difficult to maintain a separating film between them.
[0007] There are a wide variety of lubricating greases which have
been developed to lubricate interactions between e.g., metal-metal
metal-plastic parts and plastic-plastic parts. Because of design
simplicity, decreased sealing requirements and less need for
maintenance, greases are almost universally given first
consideration for lubricating bearings in electric motors,
household appliances, automotive wheel bearings, machine tools or
aircraft accessories. Greases are also used for the lubrication of
small gear drives and for many slow speed sliding applications. For
example lubricating greases are typically used to lubricate
bearings for constant velocity joints, ball joints, wheel bearings,
alternators, cooling fans, ball screws, chucks, linear guides for
machine tools, bearings and gears, each having individual
requirements for a lubricant given the forces and duress they are
under and the functions they are designed to perform. As
performance requirements of such joints, bearings and gears become
more demanding there is likewise a continued demand for lubricants
with improved physical properties to help achieve such performance
requirements.
[0008] Currently, in the automotive industry there is a determined
effort to reduce the weight of vehicles and thereby make them more
economical to operate by reducing the energy/power required. The
use of new lighter materials for certain vehicle parts has achieved
this need, to an extent, but additional means and ways of achieving
this goal are constantly being sought. For example, large (heavy)
electrical motors are required to be used to commence movement of a
vehicle from a stationary position. The power needed is partially
due to the necessity to overcome large differences in the static
and dynamic coefficients of friction of the vehicle before movement
can commence. The provision of a suitable lubricant which can
provide a very low difference in static and dynamic coefficients of
friction in such systems will result in a reduction in the
forces/power needed to commence motion from a static position. This
reduction in the required power will in turn mean that smaller and
therefore lighter in weight electric engines can be utilised.
[0009] There is also an ongoing need to provide dampening in for
example HiFi systems and also lubricants which are able to
lubricate in extreme temperature conditions e.g., temperatures
below -30.degree. C. e.g., low temperature bearings and gears.
[0010] It is the aim herein to provide silicone grease compositions
which both [0011] (i) maintain lubricity with reduced differences
between static and dynamic coefficients of friction and [0012] (ii)
have good dampening capabilities at elevated temperatures and/or
reduced temperatures (below -30.degree. C.).
[0013] There is provided herein a lubricating grease composition
comprising [0014] (a) 60 to 89.9% by weight of a silicone base
stock oil having a kinematic viscosity of from 20,000 to 100,000
mm.sup.2/s at 25.degree. C.; [0015] (b) 10 to 35% by weight of a
metal salt of a fatty acid wherein the metal is selected from the
group of lithium, calcium, aluminum, barium, titanium, zinc,
magnesium and/or sodium; and [0016] (c) 0.1 to 2% by weight of a
suitable anti-wear and/or anti-corrosion additive, wherein the
total composition is present in an amount of 100% by weight.
[0017] Base stock oils are classified by the American Petroleum
Institute (API) in five Groups, namely Groups I, II, III, IV and V.
They include natural lubricating oils, synthetic lubricating oils,
and mixtures thereof. Groups I to III relate to base stock oils
derived from petroleum based oils, while Groups IV and V relate to
synthetic base stock oils.
[0018] Silicone base stock oils are generally in Group V. They may
be used in lubricant compositions in both (metal-to-metal)
applications and critical (plastic-to-plastic) applications mainly
due to their good low and high temperature behavior. They show
chemical resistance, lubricity, thermal stability and oxidative
stability. However in respect of lubrication under high loads,
silicones, with the exception of halogenated silicones, are
generally both inferior to organic base oil as described above and
are typically more costly than organic base stock oils.
[0019] A silicone base stock oil is to be understood to be mainly a
siloxane based material having a polymeric backbone largely
consisting of silicon-oxygen atom bonds --[Si--O--]--. Silicone
base stock oils include, but are not limited to silicone polymer
fluids, which may be linear, branched and/or cyclic silicone
polymers, liquid silicone resins and/or silicone waxes. Silicone
base stock oil (a) of the composition herein has a kinematic
viscosity of from 20,000 to 100,000 mm.sup.2/s at 25.degree. C.
following the general method described in ISO 3104: 1994(en). The
terms silicone and siloxane may be used interchangeably to
designate silicone base stock oils such as trialkylsilyl terminated
polydialkylsiloxane, trialkylsilyl terminated
polyalkylalkylsiloxane and trialkylsilyl terminated
polyalkylarylsiloxanes.
[0020] Siloxanes generally conform to a polymeric backbone
consisting of units of the formula R.sub.mSiO.sub.4-m/2 in which m
is zero, 1, 2 or 3 and where m has an average value of from 1.98 to
2.5 per molecule and has a degree of polymerisation .gtoreq.2. Each
R may be the same or different and denotes, hydrogen or an organic
group.
[0021] When R is an organic group R may be selected from
hydrocarbon groups having from 1 to 45 carbon atoms, alternatively
from 1 to 20 carbon atoms, alternatively 1 to 15 carbon atoms,
alternatively 1 to 6 carbon atoms. Examples of R may include as
alkyl groups (methyl, ethyl, propyl, isopropyl, butyl, octyl,
nonyl, tetradecyl, octadecyl); cycloalkyl groups (cyclohexyl,
cycloheptyl); alkenyl groups having from 2 to 45 carbon atoms,
(vinyl, hexenyl); aryl groups having from 6 to 45 carbon atoms
(phenyl, diphenyl, naphthyl); alkaryl groups having from 7 to 45
carbon atoms (tolyl, xylyl, ethylphenyl); aralkyl groups having
from 7 to 45 carbon atoms (phenylethyl).
[0022] Alternatively when R is an organic group R may be any of the
above hydrocarbon groups wherein one or more hydrogen atoms have
been replaced with another substituent. Examples of such
substituents include, but are not limited to halogen atom
containing groups such as haloalkyl groups (chloromethyl,
perfluorobutyl, trifluoroethyl and nonafluorohexyl) and haloaryl
groups (monochlorophenyl, dibromophenyl, tetrachlorophenyl,
monofluorophenyl); oxygen atom containing groups such as carboxyl,
carbinol, ester, ether, acrylic groups and polyoxyalkylene groups
(polyoxyethylene, polyoxypropylene, polyoxybutylene); nitrogen atom
containing groups such as nitrile, amino, amido, cyano, cyanoalkyl
and urethane groups; sulphur atoms; sulphur atom containing groups
such as sulphide, sulphone, sulphate, sulphonate and mercapto
groups; phosphorus atoms; phosphorus atom containing groups such as
phosphate, phosphate and phosphonate groups.
[0023] A silicone base stock oil in the present composition may be
a cyclic, linear or branched silicone polymer.
[0024] Cyclic siloxanes have the general formula (R.sub.2SiO).sub.x
where R is as described above, and x is 3 to 20 and the total
number of carbon atoms in the R groups is between 20 and 1000.
[0025] Examples of cyclic siloxanes include
hexamethylcyclotrisiloxane (solid at 25.degree. C.),
octamethylcyclotetrasiloxane,
tetraphenyltetramethylcyclotetrasiloxane,
octaethylcyclotetrasiloxane,
tetramethyltetraoctylcyclotetrasiloxane,
pentamethylpentaoctylcyclopentasiloxane and
pentamethylpentadodecylcyclopentasiloxane.
[0026] Linear siloxanes conform to the general formula
R(SiR.sub.2O).sub.rSiR.sub.3, where R is as described above and r
is 1 to 5000 or higher such that the kinematic viscosity is within
the range of 20,000 to 100,000 mm.sup.2/s at 25.degree. C.
following the general method described in ISO 3104: 1994(en).
Linear siloxanes include polydimethylsiloxane when R is methyl and
polydiethylsiloxane when R is ethyl. Such compounds may have a wide
variety of terminal groups which typically include, for the sake of
example methyl, ethyl phenyl groups. The siloxanes herein may have
a kinematic viscosity in the range of 20,000 to 100,000 mm.sup.2/s
at 25.degree. following the general method described in ISO 3104:
1994(en).
[0027] In one alternative linear silicone base oil (a) may have the
following formula:
##STR00001##
in which Me is a methyl group and each R.sup.1, each R.sup.2 and
each R.sup.3 is individually selected from groups R as described
above, each R.sup.5 is individually selected from a hydrocarbon
group containing from 1 to 18 carbon atoms e.g., linear or branched
alkyl groups, phenyl groups and/or alkylaryl groups, alternatively
alkyl groups having from 1 to 10 carbon atoms, alternatively alkyl
groups having from 1 to 6 carbon atoms; and each R.sup.4 group is a
hydrocarbon groups having from 2 to 45 carbon atoms, alternatively
from 2 to 25 carbon atoms. As indicated above the kinematic
viscosity of the silicone base oil (a) is within the range of
20,000 to 100,000 mm.sup.2/s and wherein n is zero or an integer, v
is zero or an integer and t is zero or an integer.
[0028] In one alternative, each R', each R.sup.2, and each R.sup.3
may be independently selected from alkyl groups, of 1 to 45,
alternatively of 1 to 30 and further alternatively 1 to 16 carbon
atoms or phenyl groups containing 6 to 16 carbon atoms and each
R.sup.4 is independently an alkyl group having from 2 to 16 carbon
atoms.
[0029] Examples of linear siloxanes include polyalkylalkylsiloxane
polymers such as polymethyloctylsiloxane; polyalkylarylsiloxanes
such as polymethylphenylsiloxane; having a kinematic viscosity at
25.degree. C. of from 20,000 to 100,000 mm.sup.2/s, alternatively
of from 20,000 to 80,000 mm.sup.2/s following the general method
described in ISO 3104: 1994(en).
[0030] As well as determining the kinematic viscosity e.g.,
following the general method described in ISO 3104: 1994(en) if the
kinematic viscosity and material density are known dynamic
viscosity may be determined by the following equation
Kinematic viscosity(mm.sup.2/s)=dynamic viscosity(mPas)/material
density
[0031] The density may be measured using glass pycnometer according
to DIN 51757-2011-01 (Procedure V2). Ideal mixing is assumed for
blends of materials, meaning that the density of the blend can be
calculated from the respective values of the ingredients. The
values of dynamic viscosities were subsequently used to calculate
kinematic viscosities using the material densities tabulated
below.
[0032] The silicone base stock oil may, for example, be selected
from polydiethylsiloxane, polydimethylsiloxane,
polydimethylmethylalkylsiloxane and polymethylalkylsiloxane wherein
the alkyl groups are. The alkyl groups attached to the siloxane
polymer backbone as part of the methylalkylsiloxane units typically
have from 2 to 20 carbon atoms and may be linear or branched.
Examples may include ethyl, propyl, isopropyl, butyl, octyl, nonyl,
tetradecyl and/or octadecyl groups.
[0033] The silicone base stock oil may, for example, be selected
from trialkyl terminated polydiethylsiloxane, trialkyl silyl
terminated polydimethylsiloxane, trialkyl silyl terminated
polydimethylmethylalkylsiloxane, or trialkyl silyl terminated
polymethylalkylsiloxane. Generally the terminal alkyls in the
trialkyl silyl terminated will contain from 1 to 6 carbons,
alternatively are methyl and/or ethyl, alternatively methyls.
Again, for the avoidance of doubt, the alkyl groups attached to the
siloxane polymer backbone as part of the methylalkylsiloxane units
typically have from 2 to 20 carbon atoms and may be linear or
branched. Examples may include ethyl, propyl, isopropyl, butyl,
octyl, nonyl, tetradecyl and/or octadecyl groups.
[0034] Liquid silicone resins which may be utilized as the
component (a) include, for the sake of example, silicone resins
having two or more of the following groups
(R.sup.1.sub.3SiO.sub.1/2).sub.a (R.sup.2.sub.2SiO.sub.2/2)).sub.b
(R.sup.3SiO.sub.3/2).sub.c and (SiO.sub.4/2).sub.d with R.sup.1,
R.sup.2 and R.sup.3 as hereinbefore described. In the silicone
resins each R.sup.1, R.sup.2 and R.sup.3 may alternatively
represent an alkyl group containing from 1 to 8 carbon atoms, an
aryl group, a carbinol group, an alkoxy group (preferably methoxy
or ethoxy) or an amino group, 0.05.ltoreq.a.ltoreq.0.5;
0.ltoreq.b.ltoreq.0.3; c.gtoreq.0; 0.05.ltoreq.d.ltoreq.0.6, and
a+b+c+d=1 (with a, b, c and d being mole fractions).
[0035] The silicone base stock oil can be a blend of multiple
silicone oils described above.
[0036] The silicone base stock oil is present in an amount of from
65 to 89.9% by weight of a silicone base stock oil having a
kinematic viscosity of from 20,000 to 100,000 mm.sup.2/s at
25.degree. C. following the general method described in ISO 3104:
1994(en); alternatively in an amount of from 65 to 85% by weight of
a silicone base stock oil based on the total weight of the
composition.
[0037] One advantage of having high viscosity polymers in the
composition described herein as the silicone base stock oil is that
such a material is generally tacky to the articles being lubricated
because of the natural viscosity thereof. This avoids the need for
the addition of tackifying additives which are commonly required in
grease formulations at least partially because of the low viscosity
of the base oils used.
[0038] In accordance with the composition as described above
component (b) is a metal salt of a fatty acid wherein the metal is
selected from the group of lithium, calcium, aluminum, barium
titanium, zinc, magnesium and/or sodium. Such materials function as
thickeners in the composition as hereinbefore described. Examples
include any one or more of the lithium monocarboxylic fatty acids
or lithium hydroxymonocarboxylic fatty acids, calcium
monocarboxylic fatty acids or calcium hydroxymonocarboxylic fatty
acids, aluminum monocarboxylic fatty acids or aluminum
hydroxymonocarboxylic fatty acids barium monocarboxylic fatty acids
or barium hydroxymonocarboxylic fatty acids and titanium
monocarboxylic fatty acids or titanium hydroxymonocarboxylic fatty
acids zinc monocarboxylic fatty acids or zinc hydroxymonocarboxylic
fatty acids, magnesium monocarboxylic fatty acids or magnesium
hydroxymonocarboxylic fatty acids and/or sodium monocarboxylic
fatty acids. Component (b) may also comprise lithium, calcium,
aluminum, barium and titanium, zinc, magnesium and/or sodium salts
of fatty acids derived from animal oils or from vegetable oils,
e.g., a seed oil used in the production of metal soaps.
[0039] Preferable are the salts of monocarboxylic fatty acids or
hydroxymonocarboxylic fatty acids having 8 to 22 carbon atoms, for
example metal salts wherein the metal is selected from the group of
lithium, calcium, aluminum, barium titanium, zinc, magnesium and/or
sodium, of a lauric acid (dodecanoic acid), myristic acid
(1-tetradecanoic acid), palmitic acid (hexadecanoic acid), stearic
acid (octadecanoic acid, behenic acid (docosanoic acid),
myristoleic acid (9-tetradecenoic acid), palmitoleic acid
(hexadec-9-enoic acid), oleic acid (9Z)-Octadec-9-enoic acid, or a
linoleic acid (cis-9,12-octadecadienoic acid).
[0040] In one alternative the metal salts may include metal salts
of 12-hydroxystearic acid, 14-hydroxystearic acid,
16-hydroxystearic acid, 6-hydroxystearic acid, or
9,10-hydroxystearic acid wherein the metals are selected from
lithium, calcium, aluminum, barium and titanium, zinc, magnesium
and sodium in particular lithium. Any suitable mixture of the above
may be utilised. Particularly preferred are the lithium soaps are
derived from C10-24, preferably C15-18, saturated or unsaturated
fatty acids or derivatives thereof. One particular derivative is
hydrogenated castor oil, which is the glyceride of
12-hydroxystearic acid. 12-hydroxystearic acid is a particularly
preferred fatty acid for example 12-Hydroxy Lithium stearate.
[0041] Component (b) is present in an amount of from 10 to 35% by
weight of the total composition.
[0042] Component c) of the composition is an anti-wear and/or
anti-corrosion additive in an amount of from 0.1 to 2% by weight of
the composition. Any suitable anti-wear and/or anti-corrosion
additive may be utilised. These may include zinc dithiophosphate,
organosulphur and organo-phosphorus compounds, such as organic
polysulphides among which alkylpolysulphides; phosphates among
which trihydrocarbyl phosphate, dibutyl hydrogen phosphate, amine
salt of sulphurized dibutyl hydrogen phosphate, dithiophosphates
e.g., zinc dithiophosphate; dialkyldithiophosphates, e.g., zinc
dialkyldithiophosphates, dithiocarbamates dihydrocarbyl phosphate;
tricresyl phosphate sulphurized olefins, such as sulphurized
isobutylene, and sulphurized fatty acid esters.
[0043] Optionally the composition herein may contain dry lubricant
in an amount of up to 5% by weight of the composition,
alternatively up to 3% by weight of the composition. Any suitable
dry lubricant may be utilised when present. Examples might include
one or more selected from the list of graphite, molybdenum
disulphide, boron nitride, talc, polytetrafluoroethylene (PTFE),
calcium fluoride, cerium fluoride, and tungsten disulfide.
[0044] The composition of the present invention may contain one or
more grease additives in amounts normally used in this field of
application, to impart desirable characteristics to the grease,
such as oxidation stability and extreme pressure properties. In
particular additional thickeners and thickener complexing agents
may be introduced into the composition in addition to component
(b).
[0045] In addition to component (b) of the composition one or more
complex thickeners may be introduced. These are typically low to
medium molecular weight monobasic acids or dibasic acids or salts
thereof. In this instance the acids are not fatty acids. Examples
include benzoic acid, boric acid or a lithium borate.
[0046] Examples of additional thickeners to be used in conjunction
with component (b) might include silica, expanded graphite,
polyurea and/or clays such as hectorite or bentonite. Urea
compounds may alternatively be introduced as additional thickeners.
Such thickeners in greases include the urea group (--NHCONH--) in
their molecular structure. These compounds may be mono-, di- or
polyurea compounds. Such additional thickeners may be used at a
level of from 5 to 25% wt based on the total weight of the
composition.
[0047] As previously indicated various other conventional grease
additives may be incorporated into the lubricating greases, in
amounts normally used in this field of application, to impart
certain desirable characteristics to the grease. These might
include friction modifiers, extreme pressure additives, seal
swelling agents, rust and corrosion inhibitors, Viscosity Index
improvers, pour point depressants, anti-oxidants, free-radical
scavengers, hydroperoxide decomposers, metal passivators, surface
active agents such as detergents, emulsifiers, demulsifiers,
defoamants, compatibilizers, dispersants, and mixtures thereof.
[0048] Further additives include deposit control additives, film
forming additives, tackifiers, antimicrobials, additives for
biodegradable lubricants, haze inhibitors, chromophores, and
limited slip additives.
[0049] Examples of friction modifiers include molybdenum compounds,
aliphatic amines or ethoxylated aliphatic amines, ether amines,
alkoxylated ether amines, acylated amines, tertiary amines,
aliphatic fatty acid amides, aliphatic carboxylic acids, aliphatic
carboxylic esters, polyol esters, aliphatic carboxylic
ester-amides, imidazolines, aliphatic phosphonates, aliphatic
phosphates, aliphatic thiophosphonates and aliphatic
thiophosphates.
[0050] Examples of extreme pressure additives include organosulphur
and organo-phosphorus compounds, such as organic polysulphides
among which alkylpolysulphides; phosphates among which
trihydrocarbyl phosphate, dibutyl hydrogen phosphate, amine salt of
sulphurized dibutyl hydrogen phosphate, dithiophosphates;
dithiocarbamates dihydrocarbyl phosphate; sulphurized olefins, such
as sulphurized isobutylene, and sulphurized fatty acid esters.
[0051] Examples of seal swell agents include esters, adipates,
sebacates, azeealates, phthalates, sulphones such as
3-alkoxytetraalkylene sulphone, substituted sulpholanes, aliphatic
alcohols of 8 to 13 carbon atoms such as tridecyl alcohol,
alkylbenzenes, aromatics, naphthalene depleted aromatic compounds
and mineral oils.
[0052] Examples of rust and corrosion inhibitors include
monocarboxylic acids such as octanoic acid, decanoic acid and
dodecanoic acid; polycarboxylic acids such as dimer and trimer
acids from tall oil fatty acids, oleic acid, linoleic acid;
thiazoles; triazoles such as benzotriazole, decyltriazole,
2-mercapto benzothiazole; thiadiazoles such as
2,5-dimercapto-1,3,4-thiadiazole,
2-mercapto-5-hydrocarbyldithio-1,3,4-thiadiazole; metal
dithiophosphates; ether amines; acid phosphates; amines;
polyethoxylated compounds such as ethoxylated amines; ethoxylated
phenols; ethoxylated alcohols; imidazolines and aminosuccinic
acids.
[0053] Examples of Viscosity Index improvers include
polymethacrylates, olefin copolymers, polyisoalkylene such as
polyisobutylene, styrene-diene copolymers, and styrene-ester
copolymers such as styrene-maleic ester.
[0054] Examples of pour point depressants include wax-alkylated
naphthalenes and phenols, polymethacrylates and styrene-ester
copolymers.
[0055] Examples of anti-oxidants include phenolic antioxidants such
as 2,6-di-tert-butylphenol, tertiary butylated phenols such as
2,6-di-tert-butyl-4-methylphenol,
4,4'-methylenebis(2,6-di-tert-butylphenol),2,2'-methylenebis(4-methyl-6-t-
er t-butylphenol), 4,4'-thiobis(2-methyl-6-tert-butylphenol); mixed
methylene-bridged polyalkyl phenols; aromatic amine antioxidants;
sulphurized phenolic antioxidants; organic phosphites; amine
derivatives such as p-, p'-dioctyldiphenylamine,
N,N'-di-sec-butylphenylenediamine, 4-isopropylaminodiphenylamine,
phenyl-.alpha.-naphthyl amine, phenyl-.alpha.-naphthyl amine,
ring-alkylated diphenylamines; bisphenols and cinnamic acid
derivatives.
[0056] Examples of free-radical scavengers include zinc dialkyl
dithiophosphates, hindered phenols, and alkylated arylamines.
[0057] Examples of hydroperoxide decomposers include organo-sulphur
compounds and organo-phosphorus compounds.
[0058] Examples of metal passivators include poly-functional
(polydentate) compounds, such as ethylenediaminetetraacetic acid
(EDTA) and salicylaldoxime.
[0059] Examples of surface active agents such as detergents,
dispersants, emulsifiers, demulsifiers include alkali metal or
alkaline earth metal salts of organic acids such as magnesium
sulphonate, zinc sulphonate, magnesium phenate, zinc phenate,
lithium sulphonate, lithium carboxylate, lithium salicylate,
lithium phenate, sulphurized lithium phenate, magnesium sulphonate,
magnesium carboxylate, magnesium salicylate, magnesium phenate,
sulphurized magnesium phenate, potassium sulphonate, potassium
carboxylate, potassium salicylate, potassium phenate, sulphurized
potassium phenate; common acids such as alkylbenzenesulphonic
acids, alkylphenols, fatty carboxylic acids, polyamine, polyhydric
alcohol derived polyisobutylene derivatives.
[0060] Examples of defoamants include polysiloxanes, polyacrylates
and styrene ester polymers.
[0061] Examples of dispersants include alkenylsuccinimide such as
polyisobutylene succinimide, N-substituted polyisobutenyl
succinimides such as polyisobutenyl
succinimide-polyethylenepolyamine, succinates, succinate esters,
alkyl methacrylate-vinyl pyrrolidinone copolymers, alkyl
methacrylate-dialkylaminoethyl methacrylate copolymers,
alkylmethacrylate-polyethylene glycol methacrylate copolymers,
polystearamides, high molecular weight amines, phosphoric acid
derivatives such as bis-hydroxypropyl phosphorate.
[0062] Some additives may possess multiple properties and provide
for a multiplicity of affects. For example, graphite and molybdenum
disulphide may both be used as friction modifiers and extreme
pressure additives or functionalized soaps may be used to thicken
but also provide extreme pressure and antiwear performances to
greases.
[0063] When present in the lubricant composition of the invention,
the one or more additive(s) may be used at a level of from 0.01 to
10 wt % based on the total weight of the composition, alternatively
0.1 to 5 wt %, based on the total weight of the composition.
[0064] The composition is produced by mixing components (a), (b)
and (c) and any optional additives present, by conventional mixing
means, optionally with heating.
[0065] Lubricating compositions may be used in a variety of
applications where friction occurs between rubbing surfaces. The
surfaces may be plastic or metal.
[0066] Types of friction include sliding, rolling, static, kinetic,
stick-slip, solid (dry), boundary, mixed, wear, erosion,
elasto-hydrodynamic frictions.
[0067] The present invention includes a method to lubricate
interacting parts (e.g., metal-metal surfaces, metal-plastic
surfaces and/or plastic to plastic surface, alternatively metal to
metal surfaces) comprising: [0068] i. obtaining a lubricant
composition comprising the composition as hereinbefore described
and; [0069] ii lubricating the interacting parts with said
lubricant composition.
[0070] The composition herein may be utilised to lubricate
interactions between e.g., metal-metal and metal-plastic parts for
example bearings, e.g., lubricating bearings in electric motors,
wheel bearings, bearings in household appliances, machine tools or
aircraft accessories. Greases are also used for the lubrication of
small gear drives and for many slow speed sliding applications.
They are often utilised in constant velocity joints, ball joints,
alternators, cooling fans, ball screws, chucks, linear guides for
machine tools, and gears, each having individual requirements for a
lubricant given the forces, duress they are under and the functions
they are designed to perform. Surprisingly despite the
significantly greater viscosity of the silicone base oils herein
compared to those previously used our composition functions well.
As will be seen below it was unexpectedly identified that the
composition herein was found to have a low difference in value
between the static and dynamic friction which renders our
composition suitable for use in joints used by electrical motors to
commence movement of a vehicle from a stationary position. The
provision of our composition provides a very low difference in
static and dynamic coefficients of friction resulting in a
reduction in the forces/power needed to commence motion from a
static position. This reduction in the required power will in turn
mean that smaller and therefore lighter in weight electric engines
can be utilised. Furthermore, given the viscosity of component (a)
of our composition our composition is of a tacky nature, resulting
in tackifying agents not being required for excellent contact of
the grease to the metal and/or plastic surfaces being
lubricated.
[0071] Joints used in automobiles applications such as constant
velocity joints and ball joints especially in the metal/plastic
context and the like require both a low coefficient of friction and
as little wear as possible between the different parts of the
respective joints. Under a load, the lubricant composition herein
has been found to adhere strongly to the essential moving parts of
the joint and will form a lubricant (grease) layer with
approximately constant thickness. The present composition has
excellent adhesion/tackiness properties not least because of the
high viscosity of component (a) the silicone base stock oil. A
lubricant composition for such joints is also needed to flow
smoothly when the interacting parts (sometimes referred to as
gliding parts) change from a stationary condition to a moving
condition, and the lubricant (grease) layer needs to be maintained
without change even after repeated movement so that a stable
lubricating function is maintained. Surprisingly the compositions
as herein provided are also able to meet these requirements.
[0072] The composition herein is also suitable for the provision of
dampening in, for example, HiFi systems and also lubricants which
are able to lubricate in extreme temperature conditions e.g.,
temperatures below -30.degree. C., e.g., low temperature bearings
and gears/This because the composition, when utilised to lubricate,
will: [0073] (i) maintain lubricity with reduced differences
between static and dynamic coefficients of friction, [0074] (ii)
(ii) have good dampening capabilities at elevated temperatures
and/or reduced temperatures (below -30.degree. C.), [0075] (iii)
adhere strongly to the surfaces being lubricated to form a
"lubricating layer" between them with a relatively constant
thickness. [0076] (iv) flow smoothly at the gliding part when the
adjacent surfaces meet. Furthermore, the lubricating layer created
is successfully maintained without the need to re-lubricate after
repeated movement resulting in a stable lubricating function.
[0077] The present lubricant composition may be used in any system
that includes machine elements that contain gears of any kind and
roller bearings. Examples of such systems include electricity
generating systems, industrial manufacturing equipment such as
paper, steel and cement mills hydraulic systems, automotive drive
trains, aircraft propulsion systems, etc. Hence, they may be used
to lubricate bearings for constant velocity joints, ball joints,
wheel bearings, alternators, cooling fans, ball screws, chucks,
linear guides for machine tools, bearings and gears.
[0078] Further systems include crankcases, 2-stroke engines,
4-stroke engines, diesel engines, internal combustion engines,
gears for manual or differential transmissions, industrial
lubricants, hydraulic, compressor, turbine, metal working and metal
forming.
[0079] Further systems also include traction and torque
systems.
[0080] Operating temperatures for the use of the lubricant
composition, meaning the temperatures at which the lubricant
composition may be used for prolonged times (also called service
temperatures), range of from -55.degree. C. to +200.degree. C.
Short term peak temperatures may be higher.
[0081] The ingredients may be pre-prepared and mixed in their
pre-prepared form but alternatively they may be prepared in
situ.
EXAMPLES
[0082] The following formulation identified as Example 1 is a
composition in accordance with composition herein and which was
used throughout the following examples.
TABLE-US-00001 TABLE 1 Composition of Example 1 (Ex. 1) % by weight
of the Component Function total composition Trimethylsiloxy
terminated Base Oil 78.5 polydimethyl siloxane 30,000 mm.sup.2/s at
25.degree. C. (ISO 3104: 1994(en)) 12-Hydroxy Lithium stearate
Single Soap 21.0 Thickener Anti-wear and -corrosion 0.5
additive
[0083] The following table shows the test results of common
industrial standard tests for greases, which tests were undertaken
on the composition identified as Example 1 above and depict
.describe grease properties in general for said Example 1. The
ingredients were mixed together.
TABLE-US-00002 TABLE 2 Physical Properties of Ex. 1 grease
composition Test Standard Example 1 Nature Pasty, medium
uninterrupted Odour clearly noticeable, not disrupted Colour DIN
6167 (1980-01) white to light grey Consistency class DIN 51818
(1981-12) 0 to 1 Density DIN 51757 - 2011-01 0.96 Drop point
(.degree. C.) IP396-02 221 Unworked penetration (1/4 cone) DIN ISO
2137: 2007 317 (0.1 mm) Worked penetration (60 DIN ISO 2137: 2007
319 strokes) (0.1 mm) Oil separation after 168 DIN 51817: 2014-08
0.12 hours at 40.degree. C. (weight-%) EMCOR-Corrosion-Protection
DIN 51808: 2015-11 0 (distilled, water 168 h) (Degree of corrosion)
Flow pressure at -40.degree. C. (Pa) DIN 518051974 - 08 15,000
Water resistance (+90.degree. C.) DIN 51807-1: 1979 - 04 1-90
[0084] The difference between the static and dynamic coefficients
of friction of Example 1 (high viscosity) were then compared with
those of a variety of comparative lubricant grease compositions all
of which contained much lower viscosity silicone base stock oils
(<1000 mm.sup.2/s) at 25.degree. C. following the general method
described in ISO 3104: 1994(en) having their compositions
identified in Tables 3 to 7.
TABLE-US-00003 TABLE 3 composition of Comparative. 1 (Comp. 1)
Components Function % wt. trimethylsiloxy terminated Base oil 78.5
Polydimethyl siloxane, 200 mm.sup.2/s at 25.degree. C. 12-Hydroxy
Lithium stearate Single soap thickener 21 18% Triazole derivative
82% VCF Anti-wear and -corrosion 0.5 additive
TABLE-US-00004 TABLE 4 composition of Comparative. 2 (Comp. 2)
Components Function % wt. Trimethylsiloxy terminated Base oil 78.6
polydimethylsiloxane 350 mm.sup.2/s at 25.degree. C. 12-Hydroxy
Lithium stearate Complex thickener 14.7 component Nonanedioic Acid,
Di Lithium Salt Complex thickener 5.8 component Anti-corrosion
additive Anti-corrosion additive 0.9
TABLE-US-00005 TABLE 5 composition of Comparative. 3 (Comp. 3)
Components Function % wt. Trimethylsiloxy terminated phenylmethyl
Base oil 84.6 siloxane 500 mm.sup.2/s at 25.degree. C. in which
Ph:Me ratio 7:1 12-Hydroxy Lithium stearate Complex thickener 7.2
component Nonanedioic Acid, Di Lithium Salt Complex thickener 2.7
component Polytetrafluoroethylene (PTFE) Solid lubricant 4.6
additive 1,2-Dihydro-2,2,4-Trimethylquinoline Anti-oxidant additive
0.9 Homopolymer
TABLE-US-00006 TABLE 6 composition of Comparative. 4 (Comp. 4)
Components Function % wt. Trimethylsiloxy terminated phenylmethyl
Base oil 81.8 siloxane 100 mm.sup.2/s at 25.degree. C. in which
Ph:Me ratio 5:1 Lithium stearate Single soap 18.2 thickener
TABLE-US-00007 TABLE 7 composition of Comparative. 5 (Comp. 5)
Components Function % wt. Trimethylsiloxy terminated Base oil 83.0
phenylmethyl siloxane 125 mm.sup.2/s at 25.degree. C. in which
Ph:Me ratio 1:1 Lithium stearate Single soap 17.0 thickener
[0085] Example. 1 and the above comparatives were analysed to
determine the difference between their respective dynamic and
static coefficients of friction using a stick-slip tester from
AKE-technologies GmbH called Anti-Knarz (noise) Machine.
[0086] The Anti-Knarz (noise) Machine is sensitive enough to
measure the static and dynamic friction coefficient by way of a
ball plate tribometer-system. The tester was used for internal
pre-test selection of the grease candidate with lowest friction
level of static and dynamic friction coefficient and the smallest
difference of both. The tests were run using the parameters:
Specimen: 12.7 mm POM Ball/S-36 Q-Panel
[0087] Speed: 0.5 mm/sec
Load: 30 Newton
[0088] Cycles: 1000 (measured every 10 cycles) Running distance: 5
mm Duration of measurement: 20 sec The results are depicted in
Table 8 below.
TABLE-US-00008 TABLE 8 comparisons of Coefficients of friction and
their respective differences. Friction Coefficient .mu. Difference
Product Run .mu. static .mu. dynamic .mu. stat. - .mu. dyn. Ex. 1 1
0.15 0.11 0.040 Ex. 1 2 0.15 0.11 0.040 Ex. 1 Average 0.15 0.11
0.040 Comp. 1 1 0.18 0.13 0.050 Comp. 1 2 0.18 0.13 0.050 Comp. 1
Average 0.18 0.13 0.050 Comp. 2 1 0.15 0.11 0.040 Comp. 2 2 0.14
0.11 0.030 Comp. 2 Average 0.145 0.11 0.035 Comp. 3 1 0.28 0.21
0.070 Comp. 3 2 0.29 0.23 0.060 Comp. 3 Average 0.285 0.22 0.065
Comp. 4 1 0.14 0.1 0.040 Comp. 4 2 0.13 0.09 0.040 Comp. 4 Average
0.135 0.09 0.045 Comp. 5 1 0.15 0.11 0.040 Comp. 5 2 0.16 0.12
0.040 Comp. 5 Average 0.155 0.115 0.040
[0089] Optimal greases have as low static and dynamic coefficients
of friction as possible and as small a difference between said
static and dynamic values. It was unexpectedly identified that
Example 1 produced better or no worse results than each of the
comparatives, despite using a silicone base stock oil having a
significantly greater viscosity. The differences between the static
and dynamic viscosity coefficients can also be seen to be good for
Example. 1.
[0090] In a further series of experiments the rubber compatibility
of different rubbers with Example 1 in terms of shore hardness
change and weight change by comparing a blank rubber sample to a
grease treated rubber sample using the following methods.
[0091] 1. Rubber Compatibility Test--Weight Loss (DIN
53521-1987-11). [0092] Rubber tensile bars of shape "S2" were
cleaned lightly with a lintless textile or tissue (if needed
isopropyl alcohol was used as a cleaning fluid). The resulting
cleaned test bars were then coated completely in Example. 1 grease
composition. The resulting samples were then stored at 70.degree.
C. for 96 hours the un-treaded and treaded test pieces were cleaned
and balanced again. The weight differences were calculated and the
value reported in g and % weight difference
TABLE-US-00009 [0092] TABLE 9a Rubber compatibility test - Weight
loss (DIN 53521 - 1987 - 11). Blank sample without grease treatment
Weight before/ Result Materials Sample after (g) (%) Neoprene 1
1.5355 1.5323 -0.21 2 1.5074 1.5050 -0.16 3 1.3610 1.3584 -0.19
Polyurethane (PU) blend 1 1.0470 1.0411 -0.56 grade 2 1.1075 1.1010
-0.59 3 1.2109 1.2040 -0.57 Polyurethane (PU) Shore 1 1.0428 1.0383
-0.43 80 2 0.9746 0.9704 -0.43 3 0.8488 0.8458 -0.35
Styrene-butadiene rubber 1 0.9698 0.9649 -0.51 (SBR) 2 1.1055
1.1001 -0.49 3 0.9101 0.9064 -0.41 Ethylene propylene diene 1
1.0099 1.0052 -0.47 monomer (EPDM) 2 0.9365 0.9314 -0.54 3 0.9521
0.9458 -0.66 Acrylonitrile butadiene 1 1.2455 1.2405 -0.40 rubber
(NBR) 2 1.1763 1.1724 -0.33 3 1.0087 1.0048 -0.39 VITON .RTM. 1
1.2369 1.2334 -0.28 Fluoroelastomer 2 1.3416 1.3380 -0.27 3 1.2395
1.2363 -0.26
[0093] All blank samples showing after storing at 70.degree. c. for
96 h a weight loss between 0.16 and 0.66 weight %
TABLE-US-00010 TABLE 9b Rubber compatibility test - Weight loss
(DIN 53521 - 1987 - 11) after silicone grease had been applied
Materials (treated with Weight before/ Result Silicone Lubricant)
Sample after (g) (%) Materials Neoprene 1 1.5743 1.5554 -1.20 2
1.5794 1.5620 -1.10 3 1.6223 1.6033 -1.17 Polyurethane (PU) blend 1
1.1553 1.1452 -0.87 grade 2 1.0820 1.0727 -0.86 3 1.1973 1.1871
-0.85 Polyurethane (PU) Shore 1 0.8472 0.8405 -0.79 80 2 0.9639
0.9563 -0.79 3 0.9373 0.9303 -0.75 Styrene-butadiene rubber 1
0.7704 0.7295 -5.31 (SBR) 2 0.8559 0.8070 -5.71 3 0.8718 0.8187
-6.09 Ethylene propylene diene 1 0.9693 0.8957 -7.59 monomer (EPDM)
2 0.9566 0.8831 -7.68 3 0.9753 0.9122 -6.47 Acrylonitrile butadiene
1 1.0542 1.0305 -2.25 rubber (NBR) 2 1.0916 1.0678 -2.18 3 1.1144
1.0899 -2.20 VITON .RTM. 1 1.3550 1.3472 -0.58 2 1.2266 1.2195
-0.58 3 1.2292 1.2219 -0.59
[0094] All rubber samples showing a very good (<5%) to
acceptable (>5-<10%) weight loss after storing at 70.degree.
c. for 96 h.
[0095] 2. Rubber Compatibility Test--Shore A Hardness [0096] A
Shore hardness tester (Digi test II) (durometer) was used to
measure the depth of an indentation in the rubber material created
by a given force on a standardized presser foot following the
standard method in DIN ISO 7619-1:2012 02. Tests were made using
blank Samples (i.e., not previously treated with lubricant) and
after treating with lubricant. The results are depicted in Table 10
below.
TABLE-US-00011 [0096] TABLE 10 Rubber Compatibility Test - Shore A
Hardness Blank Sample Sample with silicone Shore Hardness grease
Shore Hardness Rubber type Difference (.DELTA.) Difference
(.DELTA.) Neoprene 2.80 2.70 Polyurethane (PU) blend -3.10 -4.30
grade Polyurethane (PU) Shore 80 -4.10 -4.70 Styrene-butadiene
rubber 2.80 6.60 (SBR) Ethylene propylene diene -1.40 5.40 monomer
(EPDM) Acrylonitrile butadiene 0.90 0.60 rubber (NBR) VITON .RTM.
-1.90 -1.30
[0097] All rubber samples showing a very good (.DELTA.<+/-5) to
acceptable (.DELTA.>+/-5-<+/-10) shore hardness change after
storing at 70.degree. c. for 96 h.
* * * * *